[Endoperez]

2d6oe: 2 six-sided dice (numbered from 1 to 6) are rolled, and every 6 is rerolled. oe means open-endedness, or rerolling. The rerolled dice are actually numbered 0 to 5 to avoid every roll with a six always being at least seven.

Page 5 of your manual has comparison chart that can be used for this, as well as many other things. The adjustment in this case would be (weapon damage + strength) - (protection * x).

Shields:
Shields have their own parry value. If a hit is scored against a unit that would have missed if not for a shield, the shield's protection value is added to the unit's normal protection. So, unit with def 8 and parry 5 shield has defence 13. Unit with attack 10 will probably beat his shieldess defence (8) but not his parry-boosted defence (13), so his protection total has about 15 added to it, depending on the shield.
Shields have a chance of negating missile fire. This feature isn't affected by the shield's protection in any way, see pg 77.

Armor-piercing damage is dealt as if the target's protection value was only half of what it actually is, but this only affects that armor-piercing damage and not other types of damage dealt to the unit. For example, a sacred unit with spear and Fire 9 bless (deals 6 points of AP fire damage) deals str+3 damage from spear, and 6 AP damage from fire.

Armor-negating damage goes through all protection, including shield parry.



I don't know how rounding goes.